The present invention relates to devices for interfacing peripherals and computers, and in particular to devices allowing peripherals supporting various functionalities to be used with a computer or computers.
Computer input peripheral devices, such as keyboards, mice, joysticks, graphics tablets and other such devices, transmit data to and receive data from computers using a variety of different protocols. Common protocols include PS/2, Universal Serial Bus (USB), Apple Desktop Bus (ADB) and a protocol used by computers supplied by Sun Microsystems Inc (Sun), amongst others. (Sun is a trade mark of Sun Microsystems Inc, registered in some countries.) Different devices of one protocol can support different functionalities. For example, different PS/2 compatible mice can have different numbers of buttons. However, not all PS/2 compatible computers are configured to utilise the full range of functionalities and therefore use a reduced range.
Also, although a peripheral device and a computer may be intended to work together using the same protocol, if the protocol does not have a tightly defined standard, then it is not uncommon for supposedly compatible computers and peripherals not to work together owing to minor differences in the way the protocol has in fact been implemented.
There are also circumstances in which it is necessary to use an input device of one protocol with a computer using a different peripheral protocol. A common instance is when a KVM (Keyboard, Video monitor and Mouse) switch is used to connect a KVM console to a plurality of computers so as to allow the plurality of computers to be operated using the common peripherals.
KVM switches are available with a microprocessor which can be entirely re-programmed by downloading new program instructions (firmware) from a computer running a terminal program via a dedicated RS232 interface. This approach is acceptable for advanced KVM devices but the RS232 connector, extra microprocessor and associated circuitry increases the size, cost and complexity of the KVM switch.
There is therefore a need for a simple device allowing a fuller functionality of peripheral devices to be utilised when operating a computer.